CN112540220A - Voltage sag detection circuit and device - Google Patents
Voltage sag detection circuit and device Download PDFInfo
- Publication number
- CN112540220A CN112540220A CN202011222793.3A CN202011222793A CN112540220A CN 112540220 A CN112540220 A CN 112540220A CN 202011222793 A CN202011222793 A CN 202011222793A CN 112540220 A CN112540220 A CN 112540220A
- Authority
- CN
- China
- Prior art keywords
- voltage
- signal
- unit
- electrically connected
- control processing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2503—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques for measuring voltage only, e.g. digital volt meters (DVM's)
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/04—Measuring peak values or amplitude or envelope of ac or of pulses
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2506—Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values ; Details concerning sampling, digitizing or waveform capturing
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention relates to a voltage sag detection circuit and a voltage sag detection device. The voltage sag detection circuit comprises a signal acquisition unit, a signal conditioning unit, an A/D conversion unit, an S conversion unit and a signal control processing unit. The voltage signal of the power supply network is acquired through the signal acquisition unit, the detected voltage signal is input to the signal conditioning unit, the signal conditioning unit conditions the voltage signal into a standard square wave signal and inputs the standard square wave signal into the A/D conversion unit, the A/D conversion unit converts the standard square wave signal into a voltage digital signal and inputs the voltage digital signal into the S conversion unit, the S conversion unit obtains the voltage amplitude of the power supply network based on the voltage digital signal, and the signal control processing unit determines whether the voltage sag occurs in the power supply network according to the obtained voltage amplitude. The invention utilizes the S conversion unit, can extract a large amount of characteristic quantities in the voltage sag detection analysis, and realizes the accurate detection of the voltage sag condition of the power supply network.
Description
Technical Field
The invention relates to the field of voltage sag, in particular to a voltage sag detection circuit and a voltage sag detection device.
Background
With the continuous development of science and technology, the living standard of people is greatly improved, the demand of people on electric power is more and more increased, and the quality of electric energy threatens the safe and stable operation of a power grid and influences the production and life of power users. Among the various power quality issues, voltage sag is a major factor in the abnormal operation of sensitive equipment. It is generally accepted that over 70% of power quality problems are caused by voltage sags. The voltage sag may cause the computer program to be disordered, the production process to be stopped, the speed regulating device to be out of order, the protection device to be in error action and the like, thereby not only causing the economic loss of users, but also causing serious casualty accidents.
At present, the existing solution for detecting the voltage sag includes detecting the voltage signal by using short-time fourier transform, but this method needs to select the window type and fix the window width, and is easily affected by noise when monitoring the voltage of the power supply network.
Disclosure of Invention
Therefore, it is necessary to provide a voltage sag detection method that is not easily affected by noise and has an adjustable time-frequency resolution change mode, in order to solve the above technical problems.
A voltage sag detection circuit, the voltage sag detection circuit comprising:
the input end of the signal acquisition unit is electrically connected with the power supply network, and the output end of the signal acquisition unit is electrically connected with the signal conditioning unit and used for acquiring a voltage signal of the power supply network;
the input end of the signal conditioning unit is electrically connected with the signal acquisition unit, and the output end of the signal conditioning unit is electrically connected with the A/D conversion unit and is used for conditioning the voltage signal into a standard square wave signal;
the input end of the A/D conversion unit is electrically connected with the signal conditioning unit, and the output end of the A/D conversion unit is electrically connected with the S conversion unit and used for converting the standard square wave signal into a voltage digital signal;
the input end of the S conversion unit is electrically connected with the A/D conversion unit, and the output end of the S conversion unit is electrically connected with the signal control processing unit and used for obtaining the voltage amplitude of the power supply network based on the voltage digital signal;
the input end of the signal control processing unit is electrically connected with the S conversion unit and used for determining whether voltage sag occurs in the power supply network according to the obtained voltage amplitude.
In one embodiment, the voltage sag detection circuit further comprises:
and the input end of the phase-locked frequency doubling unit is electrically connected with the signal conditioning unit, and the output end of the phase-locked frequency doubling unit is electrically connected with the A/D conversion unit.
In this embodiment, the phase-locked frequency doubling unit is arranged to generate an input frequency doubling signal, and then the a/D conversion unit is triggered to perform sampling, so that a measurement error caused by power grid frequency fluctuation is avoided.
In one embodiment, the signal conditioning unit comprises a low-pass filter, a voltage zero-crossing comparator and a voltage stabilizing component;
the low-pass filter is used for filtering out higher harmonics and noise in the voltage signal;
the voltage zero-crossing comparator is used for outputting an analog square wave signal;
the voltage stabilizing component is used for stabilizing the analog square wave signal and outputting a standard square wave signal.
In one embodiment, the S transformation unit is configured to perform generalized hyperbolic S transformation on the voltage digital signal to obtain an S transformation complex matrix, perform modulo operation on each element in the S transformation complex matrix to obtain an S-mode matrix, and obtain the voltage amplitude according to the S-mode matrix.
In one embodiment, the window function of the generalized hyperbolic S-transform is:
wherein f is frequency, t is time, and alpha and beta are respectively forward taper and backward taper; λ is the curvature of the window function, which is in the same dimension as time; μ is a window width adjustment factor; and y is a window width change rate adjustment factor.
In this embodiment, the window function used is a generalized hyperbolic window function, and at high frequency, the window function in the time domain is very narrow, and the time resolution is very high, and due to the asymmetry of the window function, the frequency resolution is improved. Meanwhile, the original hyperbolic window function is improved, and a window width adjusting factor and a window width change rate adjusting factor are introduced, so that the time-frequency resolution and the change mode thereof can be flexibly adjusted, and the sensitivity of a detection signal to noise is reduced.
In one embodiment, the signal control processing unit includes:
the judgment component is used for comparing the voltage amplitude with a preset threshold value, and if the voltage amplitude is greater than or equal to the preset threshold value, the judgment component takes the condition that no voltage sag occurs in the power supply network as a detection result; and if the voltage amplitude is smaller than the preset threshold value, taking the voltage sag of the power supply network as a detection result.
In one embodiment, the signal control processing unit further includes:
and the characteristic extraction component is used for obtaining the start-stop moment and the phase jump information of the voltage sag according to the S transformation complex matrix obtained by the S transformation unit if the voltage amplitude is smaller than the preset threshold.
In the embodiment, by arranging the characteristic extraction component, the start-stop time and phase jump information can be effectively extracted when the voltage sag occurs in the power supply network.
In one embodiment, the voltage sag detection circuit further comprises:
the storage unit is electrically connected with the signal control processing unit and used for storing the information processed by the signal control processing unit;
and the display unit is electrically connected with the signal control processing unit and is used for displaying the information processed by the signal control processing unit.
In one embodiment, the voltage sag detection circuit further comprises:
the alarm unit is electrically connected with the signal control processing unit and used for giving an alarm when the voltage value obtained by the processing of the signal control processing unit is lower than a preset threshold value;
and the communication unit is electrically connected with the signal control processing unit and is used for performing remote communication when the voltage value obtained by processing of the signal control processing unit is lower than a preset threshold value.
A voltage sag detection device for implementing the voltage sag detection circuit of any of the above embodiments.
The voltage sag detection circuit comprises a signal acquisition unit, a signal conditioning unit, an A/D conversion unit, an S conversion unit and a signal control processing unit. The voltage signal of the power supply network is acquired through the signal acquisition unit, the detected voltage signal is input to the signal conditioning unit, the signal conditioning unit conditions the voltage signal into a standard square wave signal and inputs the standard square wave signal into the A/D conversion unit, the A/D conversion unit converts the standard square wave signal into a voltage digital signal and inputs the voltage digital signal into the S conversion unit, the S conversion unit obtains the voltage amplitude of the power supply network based on the voltage digital signal, and the signal control processing unit determines whether the voltage sag occurs in the power supply network according to the obtained voltage amplitude. The invention avoids the selection of the window and improves the defect of fixed window function by adopting the S conversion unit, and each frequency component in the time frequency keeps direct phase relation with the original signal, so that a large amount of characteristic quantity can be extracted in the detection and analysis of the voltage sag, and the amplitude of the voltage sag can be accurately detected.
Drawings
FIG. 1 is a schematic diagram of a voltage sag detection circuit according to the present application;
FIG. 2 is a schematic diagram of a portion of a voltage sag detection circuit according to an embodiment of the present application;
FIG. 3 is a schematic diagram of a partial structure of a signal control processing unit in a voltage sag detection circuit according to an embodiment of the present application;
FIG. 4 is a schematic diagram of a partial structure of a signal control processing unit in a voltage sag detection circuit according to an embodiment of the present application;
reference numerals: the system comprises a 1-signal acquisition unit, a 2-signal conditioning unit, a 3-A/D conversion unit, a 4-S conversion unit, a 5-signal control processing unit, a 6-phase-locking frequency multiplication unit, a 7-storage unit, an 8-transmission unit, a 9-alarm unit and a 10-communication unit.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
The application provides a voltage sag detection circuit, as shown in fig. 1, the voltage sag detection circuit specifically includes:
signal acquisition unit 1, signal acquisition unit 1's input and power supply network electric connection, signal acquisition unit 1's output and 2 electric connection of signal conditioning unit, in the embodiment of this application, signal acquisition unit 1 includes 3 voltage transformer, 3 current transformer, gather electric wire netting three-phase voltage and current respectively, voltage transformer and current transformer output adopt the clamp circuit that the diode is constituteed, avoid leading to voltage transformer and current transformer output signal to surpass the 3 input range scopes of AD converting unit because of electric wire netting voltage fluctuation or accident, and then cause the damage.
The input of signal conditioning unit 2 and signal acquisition unit 1 electric connection, output and 3 electric connection of AD converting unit, in this application embodiment, signal conditioning unit 2 includes low pass filter, zero crossing comparator of voltage and steady voltage subassembly, and high order harmonic and noise in the voltage signal that low pass filter can the filtering input through zero crossing comparator output simulation square wave signal of voltage, again through steady voltage subassembly steady voltage output standard square wave signal.
The input end of the a/D conversion unit 3 is electrically connected to the signal conditioning unit 2, and the output end is electrically connected to the S conversion unit 4, for converting the standard square wave signal into a voltage digital signal, in this embodiment, the a/D conversion unit 3 adopts an AD7606 chip, which can realize simultaneous sampling of 16-bit 8 channels, and the sampling frequency can reach 200KHz at most.
The input end of the S transformation unit 4 is electrically connected with the A/D conversion unit 3, the output end is electrically connected with the signal control processing unit 5, in the embodiment of the application, the discretization form of the generalized hyperbolic S transformation is that the S transformation unit adopts a generalized hyperbolic window function:
wherein, N is the number of sampling points, j, m and N take the values of 0,1 and 2 … … N-1 respectively, and T is the sampling time.
The generalized hyperbolic S transformation is carried out by adopting a generalized hyperbolic window function expression as follows:
wherein f is frequency, t is time, and alpha and beta are respectively forward taper and backward taper; λ is the curvature of the window function, which is in the same dimension as time; mu is a window width adjusting factor and represents a selection mode of the generalized hyperbolic S transformation window width; y is a window width change rate adjustment factor and represents the change rate of the window width; by changing the parameters mu and y, the time-frequency resolution and the change mode of the generalized hyperbolic S transform can be flexibly adjusted.
The S transformation unit 5 is used for carrying out generalized hyperbolic S transformation on the voltage sampling signal to obtain an S transformation complex matrix; performing modulo calculation on each element in the S-transform complex matrix to obtain an S-mode matrix; and solving the voltage amplitude according to the S-mode matrix. The generalized hyperbolic S-transform in discrete form can be implemented by means of fast fourier algorithm and convolution theorem, and is therefore very fast. The specific implementation steps for determining the S-transform complex matrix are as follows:
1) fast Fourier transform of calculating sampling voltage signal
2) Fast Fourier transform G for calculating generalized hyperbolic window function under each frequencyHS(m,n)；
3) Translating frequency spectrum
To
4) Calculated by frequency, sample point
5) Calculating the inverse fast Fourier transform of B (m, n) to obtain S transform spectrum
The input end of the signal control processing unit 5 is electrically connected with the S conversion unit 4, and is used for determining whether a voltage sag occurs in the power supply network according to the obtained voltage amplitude.
In the embodiment of the present application, the signal control processing unit 5 includes a judging component and a feature extracting component, the judging component is configured to compare the voltage amplitude with a preset voltage sag threshold (preset threshold) of 0.9UN, and if the voltage amplitude is greater than or equal to 0.9UN, no voltage sag occurs; if the voltage amplitude is less than 0.9UN, a voltage sag occurs;
the characteristic extraction component is connected with the judgment component and is used for extracting characteristic quantity according to an S transformation complex matrix obtained in the S transformation unit 4 after voltage sag occurs, detecting and analyzing the start-stop moment and phase jump of the voltage sag, wherein the start-stop moment can be positioned by an extreme point on a slope curve of fundamental frequency, and the phase jump can be reflected by a phase sequence corresponding to the fundamental frequency in the S transformation complex matrix. Therefore, the amplitude, the starting and stopping time and the phase jump of the voltage dip can be accurately detected by flexibly adjusting the time-frequency resolution and the change mode thereof and effectively extracting and calculating the characteristic quantity of the generalized hyperbolic S transformation.
In another embodiment of the present application, the signal control processing unit 5 further connects the input signal to a mapping port of a timer input capture mode, records a difference between timer counts captured before and after capturing two adjacent rising edges of the input signal, and calculates the power supply network frequency according to the timer frequency.
In an embodiment of the present application, the voltage sag detection circuit further includes:
and the storage unit 7 is electrically connected with the signal control processing unit 5 and is used for storing the information obtained by processing of the signal control processing unit 5 and forming a historical report so as to be convenient for relevant staff to consult.
And the display unit 8 is electrically connected with the signal control processing unit 5 and is used for displaying the information processed by the signal control processing unit 5.
In an embodiment of the present application, the voltage sag detection circuit further includes:
and the alarm unit 9 is electrically connected with the signal control processing unit 5 and is used for giving an alarm when the voltage value obtained by processing of the signal control processing unit 5 is lower than a preset threshold value.
And the communication unit 10 is electrically connected with the signal control processing unit 5, and is used for performing remote communication when the voltage value obtained by processing of the signal control processing unit 5 is lower than a preset threshold value, and sending voltage sag information to a remote monitoring center.
In an embodiment of the present application, a voltage sag detection device is further included, for implementing the voltage sag detection circuit according to any one of the above embodiments.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A voltage sag detection circuit, comprising:
the input end of the signal acquisition unit is electrically connected with a power supply network, and the output end of the signal acquisition unit is electrically connected with the signal conditioning unit and used for acquiring a voltage signal of the power supply network;
the input end of the signal conditioning unit is electrically connected with the signal acquisition unit, and the output end of the signal conditioning unit is electrically connected with the A/D conversion unit and is used for conditioning the voltage signal into a standard square wave signal;
the input end of the A/D conversion unit is electrically connected with the signal conditioning unit, and the output end of the A/D conversion unit is electrically connected with the S conversion unit and is used for converting the standard square wave signal into a voltage digital signal;
the input end of the S conversion unit is electrically connected with the A/D conversion unit, and the output end of the S conversion unit is electrically connected with the signal control processing unit and used for obtaining the voltage amplitude of the power supply network based on the voltage digital signal;
the input end of the signal control processing unit is electrically connected with the S conversion unit and used for determining whether voltage sag occurs in the power supply network according to the obtained voltage amplitude.
2. The voltage sag detection circuit according to claim 1, further comprising:
and the input end of the phase-locked frequency doubling unit is electrically connected with the signal conditioning unit, and the output end of the phase-locked frequency doubling unit is electrically connected with the A/D conversion unit.
3. The voltage sag detection circuit according to claim 1, wherein the signal conditioning unit comprises a low pass filter, a voltage zero crossing comparator, and a voltage regulation component;
the low-pass filter is used for filtering out higher harmonics and noise in the voltage signal;
the voltage zero-crossing comparator is used for outputting an analog square wave signal;
and the voltage stabilizing component is used for stabilizing the analog square wave signal and outputting a standard square wave signal.
4. The voltage sag detection circuit according to claim 1, wherein the S transformation unit is configured to perform generalized hyperbolic S transformation on the voltage digital signal to obtain an S-transformed complex matrix, perform modulo operation on each element in the S-transformed complex matrix to obtain an S-mode matrix, and obtain the voltage amplitude according to the S-mode matrix.
5. The voltage sag detection circuit of claim 4, wherein the window function of the generalized hyperbolic S-transform is:
wherein f is frequency, t is time, and alpha and beta are respectively forward taper and backward taper; λ is the curvature of the window function, which is in the same dimension as time; μ is a window width adjustment factor; and y is a window width change rate adjustment factor.
6. The voltage sag detection circuit according to claim 1, wherein the signal control processing unit comprises:
the judgment component is used for comparing the voltage amplitude with a preset threshold value, and if the voltage amplitude is larger than or equal to the preset threshold value, the judgment component takes the voltage sag which does not occur in the power supply network as the detection result; and if the voltage amplitude is smaller than a preset threshold value, taking the voltage sag of the power supply network as the detection result.
7. The voltage sag detection circuit of claim 6, wherein the signal control processing unit further comprises:
and the characteristic extraction component is used for obtaining the start-stop moment and the phase jump information of the voltage sag according to the S conversion complex matrix obtained by the S conversion unit if the voltage amplitude is smaller than the preset threshold.
8. The voltage sag detection circuit according to claim 1, further comprising:
the storage unit is electrically connected with the signal control processing unit and used for storing the information processed by the signal control processing unit;
and the display unit is electrically connected with the signal control processing unit and is used for displaying the information processed by the signal control processing unit.
9. The voltage sag detection circuit according to claim 1, further comprising:
the alarm unit is electrically connected with the signal control processing unit and used for giving an alarm when the voltage value obtained by processing of the signal control processing unit is lower than a preset threshold value;
and the communication unit is electrically connected with the signal control processing unit and is used for carrying out remote communication when the voltage value obtained by processing of the signal control processing unit is lower than a preset threshold value.
10. A voltage sag detection device, wherein the voltage sag detection device is disposed in a power supply network, and is configured to implement the voltage sag detection circuit according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011222793.3A CN112540220A (en) | 2020-11-05 | 2020-11-05 | Voltage sag detection circuit and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011222793.3A CN112540220A (en) | 2020-11-05 | 2020-11-05 | Voltage sag detection circuit and device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112540220A true CN112540220A (en) | 2021-03-23 |
Family
ID=75013754
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011222793.3A Pending CN112540220A (en) | 2020-11-05 | 2020-11-05 | Voltage sag detection circuit and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112540220A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113280963A (en) * | 2021-05-26 | 2021-08-20 | 南通河海大学海洋与近海工程研究院 | Real-time cable force identification method based on improved S transformation |
| CN116449193A (en) * | 2023-06-13 | 2023-07-18 | 上海红檀智能科技有限公司 | Method and device for rapidly detecting and early warning voltage notch of intelligent circuit breaker of Internet of things |
| CN116885856A (en) * | 2023-09-01 | 2023-10-13 | 北京煜邦电力技术股份有限公司 | Electric power acquisition terminal and method based on sine function model |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103995178A (en) * | 2014-05-20 | 2014-08-20 | 江苏大学 | Voltage sag detection method for S-transformation on basis of time-frequency gathering characteristic criteria |
| CN104391207A (en) * | 2014-12-09 | 2015-03-04 | 湖南工业大学 | Voltage sag detection method adopting fundamental frequency single vector S transformation |
| EP2846432A1 (en) * | 2013-09-05 | 2015-03-11 | Siemens Aktiengesellschaft | Residual current detection method and device |
| CN104808035A (en) * | 2014-01-24 | 2015-07-29 | 华北电力大学（保定） | Method for detecting voltage sag based on generalized hyperbolic S-transformation |
| CN110879325A (en) * | 2019-12-04 | 2020-03-13 | 国网江苏省电力有限公司南通供电分公司 | Voltage sag online detection system based on advance prediction |
| CN111122941A (en) * | 2019-12-04 | 2020-05-08 | 国网湖南综合能源服务有限公司 | Kaiser window function-based voltage sag characteristic quantity detection method, system and medium for improving S conversion |
-
2020
- 2020-11-05 CN CN202011222793.3A patent/CN112540220A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2846432A1 (en) * | 2013-09-05 | 2015-03-11 | Siemens Aktiengesellschaft | Residual current detection method and device |
| CN104808035A (en) * | 2014-01-24 | 2015-07-29 | 华北电力大学（保定） | Method for detecting voltage sag based on generalized hyperbolic S-transformation |
| CN103995178A (en) * | 2014-05-20 | 2014-08-20 | 江苏大学 | Voltage sag detection method for S-transformation on basis of time-frequency gathering characteristic criteria |
| CN104391207A (en) * | 2014-12-09 | 2015-03-04 | 湖南工业大学 | Voltage sag detection method adopting fundamental frequency single vector S transformation |
| CN110879325A (en) * | 2019-12-04 | 2020-03-13 | 国网江苏省电力有限公司南通供电分公司 | Voltage sag online detection system based on advance prediction |
| CN111122941A (en) * | 2019-12-04 | 2020-05-08 | 国网湖南综合能源服务有限公司 | Kaiser window function-based voltage sag characteristic quantity detection method, system and medium for improving S conversion |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113280963A (en) * | 2021-05-26 | 2021-08-20 | 南通河海大学海洋与近海工程研究院 | Real-time cable force identification method based on improved S transformation |
| CN116449193A (en) * | 2023-06-13 | 2023-07-18 | 上海红檀智能科技有限公司 | Method and device for rapidly detecting and early warning voltage notch of intelligent circuit breaker of Internet of things |
| CN116449193B (en) * | 2023-06-13 | 2023-09-26 | 上海红檀智能科技有限公司 | Method and device for rapidly detecting and early warning voltage notch of intelligent circuit breaker of Internet of things |
| CN116885856A (en) * | 2023-09-01 | 2023-10-13 | 北京煜邦电力技术股份有限公司 | Electric power acquisition terminal and method based on sine function model |
| CN116885856B (en) * | 2023-09-01 | 2023-12-05 | 北京煜邦电力技术股份有限公司 | Electric power acquisition terminal and method based on sine function model |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112540220A (en) | Voltage sag detection circuit and device | |
| CN103630748B (en) | A kind of device and method measured for micro-grid harmonic impedance | |
| CN103257271A (en) | Device and method for detecting micro grid harmonic wave and inter-harmonics based on STM32F107VCT6 | |
| CN203287435U (en) | A micro electrical network harmonic wave and inter-harmonic wave test apparatus based on an STM32F107VCT6 | |
| CN109284933B (en) | Electronic transformer state evaluation system and method based on mathematical statistics | |
| WO2012044975A1 (en) | Method for measurement of total harmonic distortion | |
| CN106645939A (en) | Method and device for power grid frequency detection based on frequency spectrum extreme point | |
| CN112415329A (en) | Voltage sag identification method and device, computer equipment and storage medium | |
| CN116008902A (en) | Electric energy pulse generation method and system | |
| CN108414838A (en) | A kind of inverter parallel system line impedance measurement method | |
| CN110879325A (en) | Voltage sag online detection system based on advance prediction | |
| CN110412644A (en) | Photoncounting methods and device | |
| CN103134969B (en) | A kind of power factor corrector and phase voltage method of estimation | |
| CN110879326A (en) | Online detection system for positioning voltage sag disturbance point based on residual error curve | |
| CN106021855A (en) | A reactor period calculating method | |
| CN114460366A (en) | Power grid harmonic phase analysis method, system and device | |
| CN110286283B (en) | Microgrid island detection method and system | |
| KR20170006067A (en) | Apparatus for estimating frequency of power system | |
| CN202159097U (en) | DC mine elevator current converter harmonic wave detection apparatus | |
| CN113848383B (en) | Method and system for rapidly calculating fundamental frequency signals of disturbed three-phase unbalanced system | |
| CN113866524B (en) | Three-phase power unbalance degree change trend measuring method and system | |
| JPH1010163A (en) | Effective voltage value measuring apparatus | |
| CN114062824A (en) | Power quality monitoring method and device based on power distribution room | |
| CN112834807B (en) | Flicker emission level measurement method and device based on instantaneous power | |
| CN220344406U (en) | Structure for improving dynamic range of oximeter measured value |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |